Wafer-shaped hollow fiber module for in-line use in a piping system

ABSTRACT

A wafer-shaped hollow fiber module adapted for in-line use in a piping system. The piping system may include two standard bolted flange connections, and at least one wafer-shaped hollow fiber module sealed between the two standard bolted flange connections. The wafer shaped hollow fiber module includes: a cylindrical housing having an open end and a closed end having a first sealing surface and an inlet port; at least one side port through the cylindrical housing; an end cap united to the open end having a second sealing surface and an outlet port.

RELATED APPLICATION

This application is a divisional application of co-pending U.S. patentapplication Ser. No. 13/419,477 filed Mar. 14, 2012, which is adivisional application of U.S. application Ser. No. 12/477,340 (now U.S.Pat. No. 8,158,001) filed Jun. 3, 2009, which claims the benefit of U.S.provisional application Ser. No. 61/059,054 filed Jun. 5, 2008.

FIELD OF INVENTION

The instant application relates to hollow fiber modules, in particular,a wafer-shaped hollow fiber module for in-line use in a new or existingpiping system and its method of manufacture.

BACKGROUND OF THE INVENTION

A hollow fiber membrane contactor may be used for many purposes,including but not limited to, removing entrained gases from liquids,debubbling liquids, filtering liquids, and adding a gas to a liquid.Membrane contactors may be used in many different applications, forexample, a hollow fiber membrane contactor may be used for in-line pHadjustment of water.

Current designs for elongate, cylindrical hollow fiber membranecontactors include hollow fiber mats embedded in opposing annular ringsof potting material where the ends of the hollow fiber members are open.These embedded mats are then inserted into an elongate, cylindricalhousing along the major axis of the hollow fiber members to form thedevice. The current designs are effective but may have one or moreissues or problems.

One problem that current designs may have is that the housing may notallow the module to be easily installed, replaced or maintained in-linewith new or existing piping systems, like pipes, tubes, ducts, etc.Another problem that current designs may have is the amount of pressuredrop associated with moving a fluid through the device.

At least one embodiment of the instant invention of a wafer-shapedhollow fiber module for in-line use in a new or existing piping systemis designed to address one or more of these problems.

SUMMARY OF THE INVENTION

According with at least one embodiment of the instant invention includesa wafer shaped hollow fiber module for in-line use in a piping system.In this embodiment, the piping system includes two standard boltedflange connections, and at least one of the wafer-shaped hollow fibermodules sealed between the two standard bolted flange connections. In atleast one embodiment, the wafer shaped hollow fiber module includes: acylindrical housing having an open end and a closed end having a firstsealing surface with an inlet port; at least one side port through thecylindrical housing; an end cap united to the open end having a secondsealing surface with an outlet port; a stack of membrane mats within thecylindrical housing comprising a plurality of hollow fibers; a pottingmaterial bonding the membrane mats to each other and simultaneouslybonding one end of the stack to the closed end of the cylindricalhousing and bonding the other end of the stack to the end cap, therebydefining an internal chamber and at least one external chamber withinthe housing; and the inlet port and the outlet port being incommunication with the internal chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in thedrawings a form that may be presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIG. 1 is a cross-sectional perspective view of a wafer-shaped hollowfiber module according to at least one embodiment of the instantinvention.

FIG. 2 is a perspective view of a piping system with the wafer-shapedhollow fiber module from FIG. 1 installed in-line.

FIG. 3 is a cross-sectional view of the piping system of FIG. 2 with thewafer-shaped hollow fiber module from FIG. 1 installed in-line.

FIG. 4 is a diagram of one embodiment of a method of treating at leastone fluid line according to at least one embodiment of the instantinvention.

FIG. 5 is a diagram of one embodiment of a method of manufacturing thewafer-shaped hollow fiber module according to at least one embodiment ofthe instant invention.

FIGS. 6A-6C are schematic diagrams of aligned stacks of modules inaccordance with selected embodiments of the instant invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, wherein like numerals indicate like elements,there is shown in FIG. 1 an embodiment of a wafer-shaped hollow fibermodule 14. Wafer-shaped hollow fiber module 14 may be for providing ahollow fiber module for installation, replacement or to maintain in-linewith a new or existing piping system 10, as shown in FIG. 2.Wafer-shaped hollow fiber module 14 may generally include a cylindricalhousing 16, an end cap 28, a potting material 38 and a stack of membranemats 34. It may be preferred that module 14 may include or may be madeof recycled, natural, renewable, recyclable, biobased, or the likematerials, that module 14 may be made to be easily recycled, forexample, of separable components, and/or that the cylindrical housing 16may be reusable, etc. The module may be adapted for commercial,industrial, institutional, residential, military, aerospace, aeronautic,maritime, municipal, and/or the like uses.

Cylindrical housing 16 may be included with wafer-shaped hollow fibermodule 14. See FIG. 1. Cylindrical housing 16 may be for housing a stackof membrane mats 34. Cylindrical housing 16 may be any device forhousing stack of membrane mats 34. Cylindrical housing 16 may be agenerally wafer shaped housing with a closed end 20, an open end 18, andat least one side port 26. Cylindrical housing 16 may be sized toreceive stack of membrane mats 34. Cylindrical housing 16 may have anyinternal shape, including, but not limited to, a circular internalshape, or a double “D” internal shape. A potting material 38 may dividecylindrical housing 16 into an internal chamber 40 and at least oneexternal chamber 42. Cylindrical housing 16, side ports 26, and end cap28 may be made of any material, including, metal, plastic, or composite.Preferably, cylindrical housing 16 may be a molded piece. Cylindricalhousing 16, side ports 26, and end cap 28 may, for example, befabricated from a rigid material, such as acrylonitrile butadienestyrene (“ABS”) or polycarbonate. Cylindrical housing 16 may have ahousing diameter 44 defined by the distance from the center to its outeredge.

In one embodiment, cylindrical housing 16 may be dimensioned forproviding the shape and size of module 14 to allow it to be positionedbetween two standard bolted flange connections 12 of piping system 10(see FIGS. 2 and 3). For example, for a 4 inch diameter pipe, housingdiameter 44 may be approximately 6.75 inches. This may allow module 14to be easily installed, replaced or maintained in between the bolts 13of a standard bolted flange connection 12 adapted to fit a 4 inchdiameter pipe 62.

End cap 28 may be united to open end 18 of cylindrical housing 16. SeeFIG. 1. End cap 28 may be for closing cylindrical housing 16. Afterstack of membrane mats 34 may be inserted into cylindrical housing 16,end cap 28 may be united to open end 18 of cylindrical housing 16.Preferably, end cap 28 may be united by an air-tight seal to theexterior walls of cylindrical housing 16. Such sealing means may includegluing, welding, spin welding, threading, O-rings, and the like. Anoutlet port 32 may be included in end cap 28. End cap 28 may alsoinclude a second sealing surface 30. In one embodiment, end cap 28 mayinclude an annular groove on the inside for allowing air flow throughall of headspace 70.

An inlet port 24 and an outlet port 32 may be included in wafer-shapedhollow fiber module 14. See FIG. 1. Closed end 20 may include inlet port24 for receiving a fluid into cylindrical housing 16. Circular inletport 24 may be defined by an opening 25 in closed end 20. End cap 28 mayinclude outlet port 32 for discharging the fluid from cylindricalhousing 16. Circular outlet port 32 may be defined by an opening 33 inend cap 28. Inlet port 24 and outlet port 32 may be in communicationwith each other through internal chamber 40. In combination, inlet port24 and outlet port 32, may allow a fluid line or stream to be movedthrough cylindrical housing 16 in internal chamber 40. Inlet port 24 andoutlet port 32 may be reversible allowing a fluid line to flow throughwafer-shaped module 14 in either direction. Inlet port 24 and outletport 32 may be openings in closed end 20 and end cap 28, respectively.These openings in closed end 20 and open end 18 may be any shape,including, but not limited to, circular.

The fluid line may be any fluid line, including, but not limited to aliquid line, a gas line, a vacuum line, an ambient air line, asupercritical fluid, or any other fluid line depending on the desiredapplication of module 14. Liquid, or a liquid line, as used herein maybe any type of liquid, including, but not limited to: RO Permeate, ROConcentrate, ground water, surface water, deionized water, distilledwater, ultrapure water, developer solution, coating solution, urine,blood, chemicals, liquids for human consumption, or any other liquids ormixtures. Gas or a gas line, as used herein may be any type of gas,including, but not limited to: flue gas, vent gas, Ammonia, Argon,Hydrogen Sulfide, Hydrogen Chloride, Chlorine water, CO₂, SO₂, NO₂/NO(NO_(x)), Ammonia, H₂S, or any other gases or mixtures.

At least one side port 26 may be provided in cylindrical housing 16. SeeFIGS. 1 and 2. Side ports 26 may be anywhere between open end 18 andclosed end 20. Side ports 26 may be in communication with hollow fibers36 of stack 34 via external chambers 42. Preferably, there should be oneside port 26 positioned at the center of every external chamber 42.Additionally, each side port 26 may be provided with a detachablefitting including, but not limited to, quick-connect fittings, threadedfittings, compression fittings, twist-lock fittings, Luer fitting, orother fittings for connection to a vacuum line, gas line, liquid line,or any other type of fluid line. In one embodiment, side ports 26 may befor providing a vacuum or partial vacuum to hollow fibers 36 viaexternal chambers 42. In another embodiment, side ports 26 may be forsweeping a gas through module 14 from one external chamber 42 throughhollow fibers 36, to another external chamber 42. In yet anotherembodiment, side ports 26 may be for providing pressurized gas to hollowfibers 36 via external chamber or chambers 42. In yet anotherembodiment, side ports 26 may be for moving a liquid through hollowfibers 36 via external chamber or chambers 42.

A first sealing surface 22 may be included on closed end 20. See FIG. 1.First sealing surface 22 may be for providing a surface to sealwafer-shaped hollow fiber module 14 with standard bolted flangeconnection 12 b (it should be understood module 14 is reversible andfirst sealing surface 22 may be sealed to bolted flange connection 12 aor 12 b). See FIG. 2. First sealing surface 22 may be any surface onclosed end 20 capable of sealing wafer shaped hollow fiber module 14with standard bolted flange connection 12 b, including, but not limitedto, a flat surface. This flat surface may be sealed to standard boltedflange connections 12 by any means, including a flat wall or a standardgasket (such as a plastic gasket, a rubber gasket, an o-ring, a paperannular gasket, gel, caulk or the like). In one embodiment, firstsealing surface 22 may be defined by a first outside radius 50 and afirst inside radius 52. First outside radius 50 may be the radius ofcylindrical housing 16 and first inside radius 52 may be the radius ofinlet port 24. In one embodiment, first sealing surface 22 may bedefined by a difference between first outside radius 50 and first insideradius 52 of at least about 0.1 inches. In a preferred embodiment, firstsealing surface 22 may be defined by a difference between first outsideradius 50 and first inside radius 52 of at least about 0.188 inches.

A second sealing surface 30 may be included on end cap 28. See FIG. 1.Second sealing surface 30 may be for providing a surface to sealwafer-shaped hollow fiber module 14 with standard bolted flangeconnection 12 a (it should be understood module 14 is reversible andsecond sealing surface 30 may be sealed to bolted flange connection 12 aor 12 b). See FIG. 2. In one embodiment, second sealing surface 30 maybe the same size as first sealing surface 22 but on the opposite end ofwafer-shaped hollow fiber module 14. Second sealing surface 30 may beany surface on end cap 28 capable of sealing wafer shaped hollow fibermodule 14 with standard bolted flange connection 12 a, including, butnot limited to, a flat surface. This flat surface may be sealed tostandard bolted flange connections 12 by any means, including a flatwall or a standard gasket (such as a plastic gasket, a rubber gasket, ano-ring, a paper annular gasket, gel, caulk or the like). In oneembodiment, second sealing surface 30 may be defined by a second outsideradius 56 and a second inside radius 58. Second outside radius 56 may bethe radius of end cap 28 and second inside radius 58 may be the radiusof outlet port 32. In one embodiment, second sealing surface 30 may bedefined by a difference between second outside radius 56 and secondinside radius 58 of at least about 0.1 inches. In a preferredembodiment, second sealing surface 30 may be defined by a differencebetween second outside radius 56 and second inside radius 58 of at leastabout 0.188 inches.

Stack of membrane mats 34 may be inserted into cylindrical housing 16.See FIG. 1. The stack of membrane mats 34 may be sandwiched betweenclosed end 20 and end cap 28. Potting material 38 may bond stack 34together and hold stack 34 in place in cylindrical housing 16. Themembrane mats of stack 34 may be stacked so that hollow fiber members 36of each membrane mat are aligned, thus, allowing a gas to be sweptthrough wafer-shaped hollow fiber module 14. The membrane mats of stack34 may also be stacked so that hollow fiber members 36 of every othermembrane mat are perpendicularly aligned allowing a gas to be sweptthrough in two different directions in module 14 or allowing twodifferent gases to be swept through module 14. The membrane mats may bewoven, knitted, or otherwise joined together in generally planarstructures containing a plurality of joined together hollow fibermembers 36. The membrane mats may be stacked substantially perpendicularto the longitudinal axis of cylindrical housing 16. The dimension of themembrane mats of stack 34 may be slightly smaller than cylindricalhousing 16 so that, when stack 34 may be inserted into cylindricalhousing 16, a headspace 70 may be created between the peripheral edge 68of stack 34 and the interior wall of cylindrical housing 16 (see FIG.1). The membrane mats of stack 34 may be cut to any shape, including butnot limited to, circular or a double “D” shape.

In accordance with at least one embodiment, the effective stack 34 ofmembrane mats aspect ratio (the “Effective Stack Aspect Ratio”) isdefined as the ratio of the effective stack diameter (the diameterinside the potting material or the diameter of the inlet opening,whichever is less) relative to the stack thickness. For example, inaccordance with selected embodiments, the Effective Stack Aspect Ratiomay be in the range of about 1 to 8, preferably from about 1 to 6, andmore preferably from about 1 to 4, most preferably from 1.5 to 3. Itbeing understood that, depending on the specific use of the module, thedesired pressure drop, the module manufacturing process, and/or thelike, the Effective Stack Aspect Ratio may be larger or smaller.

In accordance with at least certain specific examples, modules 14 mayinclude membrane mat stacks with the following approximate effectivestack diameters and stack thicknesses: 1 inch diameter and ½ inchthickness, 2 inch diameter and ¾ inch thickness, 3 inch diameter and 1inch thickness, 4 inch diameter and 1.5 inch thickness, 6 inch diameterand 3 inch thickness, 8 inch diameter and 3 inch thickness, and thelike.

Hollow fiber members 36 may be included in stack of membrane mats 34.See FIG. 1. Hollow fiber members 36 may have open ends that communicatewith side ports 26 via external chamber or chambers 42. Hollow fibermembers 36 may be for communicating between internal chamber 40 andexternal chamber or chambers 42 allowing, for example, removal ofentrained gases from a liquid, debubbling of a liquid, filtering of aliquid, adding a gas to a liquid, humidifying a gas, or the like. In oneembodiment, hollow fiber members 36 may extend from internal chamber 40through potting material 38 into external chamber or chambers 42. Hollowfiber members 36 of stack of membrane mats 34 may be of like materialsand properties, or may be of various materials and/or properties. Hollowfiber members 36 may be fibers having a lumen and a wall surrounding thelumen. Hollow fiber members 36 may have solid walls, porous walls, ormicroporous walls (e.g., symmetric pores, asymmetric pores, skinnedmembranes and the like). Hollow fiber members 36 may be made of anysuitable materials. Such materials include polyolefins (e.g.,polyethylene, polypropylene, polybutene, poly methyl pentene),polysulfones (e.g., polysulfone, polyethersulfone, polyarylsulfone),cellulose and its derivations, PVDF, poly phenyl oxide (PPO), PFAA,PTFE, other fluorinated polymers, polyamides, poly ether ether ketone(PEEK), polyether imides (PEI), polyimides, ion-exchange membranes(e.g., Nafion®), etc.

Potting material 38 may be for providing a fluid-tight annular wall, orpartial annular walls, within wafer-shaped hollow fiber module 14. SeeFIG. 1. Potting material 38 may be a fluid-tight annular wall or partialannular walls that divide cylindrical housing 16 into an internalchamber 40 and at least one external chamber 42. The fluid-tight annularwall or partial annular walls defined by potting material 38 may bebonded to the closed end 20 and end cap 28, and may be furthercontinuous or integral between each membrane mat of stack 34. This mayallow potting material 38 to distribute the strength of the device tocylindrical housing 16 and end cap 28. Potting material 38 may maintaina fluid-tight engagement between cylindrical housing 16 and stack ofmembrane mats 34 between closed end 20 and end cap 28. Potting material38 may be any material, for example, any suitable thermosettingmaterials or any suitable thermoplastic materials. Exemplary materialsfor potting material 38 include, but are not limited to, epoxy,polyolefins, and polyurethane.

Internal chamber 40 may be divided by potting material 38 from externalchamber or chambers 42 within cylindrical housing 16. See FIG. 1.Internal chamber 40 may be in communication with inlet port 24 andoutlet port 32. Internal chamber 40 may be for allowing a fluid line orstream (gas, liquid, air, etc.) to move through stack of membrane mats34 in wafer-shaped hollow fiber module 14. Internal chamber 40 may havea diameter which is equal to the diameter of the surrounding pottingmaterial 38.

At least one external chamber 42 may be included in cylindrical housing16. See FIG. 1. External chamber or chambers 42 may be for providing aspace for the peripheral edge 68 of stack of membrane mats 34 where theends of hollow fiber members 36 may remain open and communicate withside ports 26. A headspace 70 may be included in external chamber orchambers 42. External chambers 42 may allow hollow fiber members 36 tocommunicate from headspace 70 to side ports 26.

Headspace 70 may be included within external chambers 42. See FIG. 1.Headspace 70 may be defined by the space between the peripheral walls ofstack of membrane mats 34 and the interior surface of cylindricalhousing 16. Headspace 70 may allow communication between side ports 26and the open ends of the hollow fiber members 36 of the stack ofmembrane mats 34. In one embodiment, headspace 70 may include aplurality of baffles for directing fluid flow through headspace 70.

Wafer-shaped hollow fiber module 14 can be inserted as a short spoolpiece (known in the art as a wafer) between two standard bolted flangeconnections 12. See FIG. 2. Inserting wafer-shaped hollow fiber module14 between two standard bolted flange connections 12 may allow module 14to be easily installed, replaced, or maintained in-line with a new orexisting piping system 10. For purposes of this invention, module 14being installed, replaced or maintained “in-line” with new or existingpiping systems means that module 14 is installed directly in the flowpath of the conduits of the piping system. Standard bolted flangeconnections 12 may be connected to a conduit 62 to form piping system10.

Piping system 10 may be any new or existing piping system, including,but not limited to, a pipe system, a duct system, a tube system, or anyother conduit system of the like. Piping system 10 may include any knownpiping system components. In one embodiment, piping system 10 mayinclude wafer-shaped hollow fiber module 14 installed between twostandard bolted flange connections 12. See FIGS. 2 and 3. Piping system10 may include standard bolted flange connections 12 being connected toa conduit 62. Conduit 62 may be any conduit, including, but not limitedto, a pipe, a duct, a tube, or any other conduit of the like. Pipingsystem 10 may have any size conduit. In one embodiment, piping system 10may have a conduit with a diameter between ½ inch and 24 inches.

Standard bolted flange connections 12 may be included in piping system10. See FIG. 2. Standard bolted flange connections 12 may be forallowing wafer-shaped hollow fiber module 14 to be used in-line with anynew or existing piping system. Standard bolted flange connections 12 maybe any standard bolted flange connections capable of allowingwafer-shaped hollow fiber module 14 to be used in-line with any new orexisting piping system, including, but not limited to, any size, anymaterial and any shape bolted flange connections. In one embodiment,standard bolted flange connections 12 may be Japanese IndustrialStandard (“JIS”) bolted flange connections. In another embodiment,standard bolted flange connections 12 may be American National StandardsInstitute (“ANSI”) bolted flange connections by the American StandardAssociation (“ASA”). The two standard bolted flange connections 12(represented by 12 a and 12 b in FIG. 2) may be connected by a pluralityof bolts 13 and may be sealed to both sides of wafer-shaped module 14 bya first seal 48 and a second seal 54.

Plurality of bolts 13 may be included in standard bolted flangeconnections 12. See FIGS. 2 and 3. Bolts 13 may be for connecting boltedflange connections 12 on each side of wafer-shaped module 14. Pluralityof bolts 13 may include any number of bolts, including, but not limitedto, 4 bolts, 5 bolts, 6 bolts, 7 bolts, 8 bolts, 12 bolts, 16 bolts, or20 bolts. Bolts 13 may have any diameter. Bolts 13 may have a diameterslightly smaller than a diameter 47 of the associated bolt holes. SeeFIG. 3. For example, bolts 13 may have a diameter of about ⅛ inch lessthan bolt hole diameter 47. Bolt hole diameter 47 may be any distance.In order to install module 14 between two standard bolted flangeconnections 12, at least half of bolts 13 may be removed and theremaining bolts may be loosened to allow module 14 to be positionedbetween the two flange connections 12. Once module 14 is positionedbetween the two flange connections 12, the removed bolts 13 may beinserted back in their respective bolt holes. Bolts 13 may then betightened to create a seal between standard bolted flange connections 12and wafer-shaped module 14.

Plurality of bolts 13 may have a bolt circle diameter 46 defined by thedistance from the center of standard bolted flange connection 12 to thecenter of each bolt 13. The inside portions of bolts 13 may positionwafer-shaped hollow fiber module 14 in between standard bolted flangeconnections 12. As a result, housing diameter 44 should be approximateto the difference between bolt circle diameter 46 and bolt hole diameter47. In one embodiment, housing diameter 44 may be slightly smaller thanthe difference between bolt circle diameter 46 and bolt hole diameter47. This may allow module 14 to be more easily installed in betweenplurality of bolts 13. In another embodiment, housing diameter 44 may beapproximately equal to the difference between bolt circle diameter 46and bolt hole diameter 47. In another embodiment, housing diameter 44may be approximately equal to the provided tolerance between bolt circlediameter 46 and bolt hole diameter 47. In yet another embodiment,housing diameter 44 may be about 0.015 inches smaller than thedifference between bolt circle diameter 46 and bolt hole diameter 47.

The table below gives examples of approximate sizes for the diameter ofcylindrical housing 16 based on what diameter piping system module 14 isto be installed in-line with (see FIG. 3):

Housing Diameter = Piping Bolt Circle Bolt hole Bolt Circle DiameterDiameter diameter Diameter - Bolt hole (in.) (in.) (in.) No. of Boltsdiameter (in.) ½ 2.38 0.62 4 1.76 ¾ 2.75 0.62 4 2.13  1 3.12 0.62 4 2.51¼ 3.5 0.62 4 2.88 1½ 3.88 0.62 4 3.26  2 4.75 0.75 4 4 2½ 5.5 0.75 44.75  3 6 0.75 4 5.25 3½ 7 0.75 8 6.25  4 7.5 0.75 8 6.75  5 8.5 0.88 87.62  6 9.5 0.88 8 8.62  8 11.75 0.88 8 10.87 10 14.25 1.00 12 13.25 1217 1.00 12 16.00 14 18.75 1.12 12 17.63 16 21.25 1.12 16 20.13 18 22.751.25 16 21.5 20 25 1.25 20 23.75 22 27.25 1.38 20 25.87 24 29.5 1.38 2028.12

These numbers in the above chart are based on ANSI B16.5 Class 150Forged Flanges. However, these numbers are just representative of thecalculations to determine housing diameter 44 and the invention is notlimited to these particular bolted flange connections.

First seal 48 and second seal 54 may be included in piping system 10.See FIG. 2. First seal 48 may seal bolted flange connection 12 a tosecond sealing surface 30 of end cap 28 and second seal 54 may sealbolted flange connection 12 b to first sealing surface 22 of closed end20, or vice versa. First seal 48 and second seal 54 may be any type ofseals adapted to seal bolted flange connections 12 to wafer-shapedmodule 14, including, but not limited to, flat surfaces or standardbolted flange gaskets.

Wafer-shaped hollow fiber module 14 may provide several performanceenhancements over other devices known in the art for removing entrainedgases from liquids or debubbling liquids. These advantages include, butare not limited to: minimal shell side pressure drop due to very smalltransverse flow distance and maximum cross sectional flow area; module14 may be easily installed, replaced, or maintained into new or existingpiping systems with minimal reconfiguration (most existing designs arelarge and often involve complicated piping modifications); low costmanufacturing due to the known manufacturing technology with membranemats (see, for example, US Patent Publication Nos. 2006/0163140 and2007/0278145); and the design is stackable (in other words, you can putseveral wafers back to back or back to front in series).

For example, because of its design, wafer-shaped hollow fiber module 14may be installed and sealed between two standard bolted flangeconnections 12. The wafer shape of module 14 allows it to be easilyinstalled (or later replaced or maintained) in-line with new or existingpiping systems, like piping system 10. Also because of its wafer-shapeddesign, with a relatively low profile compared to its diameter, hollowfiber module 14 may provide a less restrictive flow path from inlet port24 to outlet port 32, which results in less pressure drop in the fluidmoving through internal chamber 40. This pressure drop is represented byarrow 66 in FIG. 2. The less pressure drop the fluid experiences movingthrough internal chamber 40, the less effect wafer-shaped module 14 mayhave on the fluid line in piping system 10. In one embodiment, pressuredrop 66 through internal chamber 40, as measured by the pressure dropbetween the two standard bolted flange connections 12, may be less thanabout 1.5 psi at a gas flow rate of 10 Standard Liters/minute for aninternal chamber 40 with approximately a 4 inch diameter. In a preferredembodiment, the pressure drop through internal chamber 40 between thetwo standard bolted flange connections 12, may be less than about 0.1psi at a gas flow rate of 10 Standard Liters/minute for an internalchamber 40 with approximately a 4 inch diameter. In one embodiment, thepressure drop (dP) for a sodium chloride brine solution with a 1.0liters/minute flow rate may be less than 1.0 psi for a module 14 with aninternal chamber 40 with approximately a 4 inch diameter and a stack 34of membrane mats 34 with approximately a 2 inch thickness. In oneembodiment, the pressure drop for water may be less than 1.5 psi for a10 liters/minute flow through an internal chamber 40 with a 4 inchdiameter. As a result of these enhanced performances, wafer-shapedhollow fiber module 14 may be easily positioned (installed, replaced ormaintained) in-line with new or existing piping systems.

Wafer-shaped hollow fiber module 14 may be ideally suited for a numberof gas transfer applications that require gas treating (as opposed towater treating). Examples include, but are not limited to: CO₂, SO₂,NO₂/NO (NO_(x)), Ammonia, H₂S, (or any other undesirable species)removal from Air or Biogas in a scrubbing process using chemicalabsorbents or non-chemical absorbents; adding humidity or removinghumidity from Air or Process gases by means of water vapor transferbetween gas and liquid phases. In both examples of gas treatingapplications listed above, the gas phase flows on the shell side (theoutside) and the liquid flows through the inside of hollow fibers 36.Because of the essentially negligible pressure drop on the shell side,it may be possible to install these devices ‘in-line’ without a need forupgrading existing air-moving equipment (blowers or compressors).

The instant wafer-shaped hollow fiber module 14 is not limited to gasstreams. It will also work very effectively for degassing and gassingapplications of liquid streams, such as in-line carbonation ofbeverages, in-line pH adjustment of water, and stripping of dissolvedgases from aqueous solutions. In these applications water will flow onthe shell side, and the gas phase (at elevated pressures or undervacuum), will flow through the lumen side.

With reference to FIG. 6, another opportunity for this device is tostack multiple such modules 14 end to end, each with the same ordifferent fiber types. For example, one wafer-shaped module 14 couldselectively remove one component from a gas stream, a second couldselectively remove a different component, and a third could be used forheat exchanging, filtration, and so forth. FIGS. 6A shows two modules,6B shows three modules, and 6C shows five modules. As would beunderstood, longer bolts may be required and gaskets may be usedtherebetween.

In operation, wafer-shaped hollow fiber module 14 may be used in-linewith a new or existing piping system 10 to remove entrained gases from afluid, debubble a fluid, filter a fluid, add gas to a liquid, orhumidify a fluid. For example, a first fluid line (i.e., gas, liquid,air, etc.) may be introduced into wafer-shaped hollow fiber module 14via inlet port 24 and exit via outlet port 32 (or vice versa). As thefluid travels over the external surfaces of the hollow fiber members 36,gases may be removed (entrained gases or bubbles) or added via a secondfluid line (gas, liquid, air, vacuum, etc.), and unwanted materials maybe blocked (filtration). Depending upon the use of the module, thecharacteristics of the hollow fibers 36 may change (different types ofhollow fibers may be used and/or different arrangements of hollow fibersmay be used).

In the removal of entrained gases mode, debubbling mode and or filteringmode, as the liquid travels through internal chamber 40, the gases maybe removed by passing through the wall of the hollow fiber members 36,into the lumen, and out through side ports 26 by way of headspace 70 andexternal chamber 42. Removal of the gases may be facilitated byapplication of a vacuum or partial vacuum by way of side ports 26.Removal of the gases may also be facilitated by sweeping a gas throughwafer-shaped hollow fiber module 14 by way of side ports 26. Gases thatmay be swept through wafer-shaped module 14 by way of side ports 26 tofacilitate removal of gases from a liquid include, but are not limitedto, carbon dioxide, nitrogen, oxygen, etc. When wafer-shaped module 14may have more than one side port 26, ambient air may also be used infacilitating removal of gases from a liquid. One side port 26 may beleft open while the other side ports 26 are hooked up to a vacuum line.Thus, when the vacuum is applied, ambient air from outside ofwafer-shaped module 14 may be swept through wafer-shaped module 14.Sweeping a gas through wafer-shaped module 14 may also facilitateremoval of any condensation buildup in wafer-shaped module 14. In atleast one filtration mode, contaminated fluid is introduced via inletport 24 (or outlet port 32) and exits via side ports 26 (or vice versa).Fluid travels through the hollow fiber members 36 from internal chamber40 to the external chamber or chambers 42 where the walls of the hollowfiber members 36 block contaminants.

Alternatively, in the adding a gas to a liquid mode, gases (such ascarbon dioxide, nitrogen, oxygen, etc.) may be introduced into a liquid.As the liquid flows through internal chamber 40 via inlet port 24 oroutlet port 32, the gas may be introduced through side ports 26 at alower pressure than the liquid in internal chamber 40. The lowerpressure allows the gas to absorb into the liquid, which may reducebubbling of the gas in the liquid. Gas may then move from side ports 26to headspace 70 and into hollow fiber lumens and out through the wall ofthe hollow fiber members 36 into the liquid.

In the removal of gases, like CO₂, SO₂, NO₂ and/or other undesirablespecies from air or biogas mode, as the air or biogas enters throughinternal chamber 40, the CO₂, SO₂, NO₂ and/or other undesirable speciesmay be removed selectively by passing through the wall of the hollowfiber members 36, into an absorbent liquid in the lumen, with the liquidflowing out through side ports 26 by way of headspace 70 and externalchamber 42. Removal of the CO₂, SO₂, NO₂ and/or other undesirablespecies may be facilitated if the gas species chemically reacts with theliquid.

In the humidifying or dehumidifying a fluid stream mode (gas or liquid),as the fluid stream enters through internal chamber 40, the fluid streammay be humidified or dehumidified by passing a pressurized liquidthrough hollow fiber members 36 via side ports 26 and allowing vaporfrom the liquid to pass through the wall of the hollow fiber members 36,into internal chamber 40. As should be understood, the treatment of oneor more fluid streams may also include such processes as osmosis,homeostasis, equilibrium, adding solvent, dissolving one fluid intoanother, absorption, reducing the concentration of a fluid (by forexample, adding water), and any other such processes.

As shown in FIG. 4 and in at least one embodiment, a method 72 oftreating a fluid line may be included in the instant invention. Method72 may include the steps of: a step 74 of providing at least onewafer-shaped hollow fiber module 14: a step 76 of installingwafer-shaped hollow fiber module 14 into piping system 10 between twostandard bolted flange connections 12; a step 78 of attaching side ports26 of wafer-shaped hollow fiber module 14 to a first fluid stream; and astep 80 of passing a second fluid line or stream through internalchamber 40 of wafer-shaped hollow fiber module 14 via piping system 10.

Step 76 of installing wafer-shaped hollow fiber module 14 into pipingsystem 10 between two standard bolted flange connections 12 may beincluded in method 72. See FIG. 3. Step 76 may include any steps forinstalling wafer-shaped hollow fiber module 14 between two standardbolted flange connections 12. Step 76 could be installing a newwafer-shaped hollow fiber module 14 or it could be replacing ormaintaining a current module 14. In one embodiment, step 76 may includethe steps of: inserting no more than half of bolts 13 into theirrespective holes on two standard bolted flange connections 12 (must beadjacent holes so that at least half of the two standard bolted flangeconnections 12 is open to allow module 14 to be inserted); insertingmodule 14 in between standard bolted flange connections 12; utilizingthe inserted bolts 13 to position module 14; inserting the remainingbolts 13; and tightening bolts 13, thereby, sealing module 14 in betweentwo standard bolted flange connections 12.

A step 82 of removing entrained gases, debubbling or filtering a liquidmay be included in one embodiment of method 72 of treating a fluid linewith wafer-shaped module 14. See FIG. 4. Step 82 may include any stepsfor removing entrained gases, debubbling or filtering a liquid,including, but not limited to, the steps of: a step 84 of attaching thefirst fluid line to a vacuum or partial vacuum; and a step 86 of movingthe liquid through the second fluid line; whereby, removal of entrainedgases, debubbling, or filtering of the liquid is performed via thevacuum or partial vacuum on side ports 26.

A step 88 of sweeping a gas through a liquid may be included in oneembodiment of method 72 of treating a fluid line with wafer-shapedhollow fiber module 14. See FIG. 4. Step 88 may include any steps forsweeping a gas through a liquid, including, but not limited to, a step90 of passing a gas through the first fluid line from one side port 26through hollow fibers 36 and out of the other side port 26; and a step92 of moving a liquid through the second fluid line; whereby, a gas isswept through the liquid by the gas flowing through hollow fibers 36. Inthis embodiment, wafer-shaped hollow fiber module 14 may comprise twoside ports 26 in communication with two separate external chambers 42.

A step 94 of adding a gas to a liquid may be included in one embodimentof method 72 of treating a fluid line with wafer-shaped hollow fibermodule 14. See FIG. 4. Step 94 may include any steps for adding a gas toa liquid, including, but not limited to, the steps of: a step 96 ofpassing a pressurized gas through the first fluid line from one sideport 26 through hollow fibers 36 and out of the other side port 26; anda step 98 of moving a liquid through the second fluid line; whereby thepressurized gas is added to the liquid by the gas flowing through hollowfibers 36.

A step 100 of removing CO₂, SO₂, NO₂ and/or other undesirable speciesmay be included in one embodiment of method 72 of treating a fluid linewith wafer-shaped module 14. See FIG. 4. Step 100 may include any stepsfor removing CO₂, SO₂, NO₂ and/or other undesirable species, including,but not limited to, the steps of: a step 102 of moving a liquid througha first fluid line via side ports 26; and a step 104 of passing air orbiogas through a second line via inlet port 24 and outlet port 32;whereby, CO₂, SO₂, NO₂ or other undesirable species may be removed fromthe air or biogas via the liquid through hollow fibers 36.

A step 106 of humidifying or dehumidifying a fluid stream may beincluded in one embodiment of method 72 of treating a fluid line withwafer-shaped hollow fiber module 14. See FIG. 4. Step 106 may includeany steps for humidifying or dehumidifying a fluid stream, including,but not limited to, the steps of: a step 108 of moving a pressurizedliquid through a first fluid line via said side ports 26; and a step 110of passing a fluid stream through a second fluid line via said inletport 24 and said outlet port 32; whereby, the fluid stream may behumidified or dehumidified via transfer of water vapor between the gasstream and the pressurized liquid moving through hollow fibers 36.

Wafer-shaped hollow fiber module 14 may be preferably manufactured asfollows:

Wafer-shaped hollow fiber module 14 can be produced usingliquid-on-liquid potting technology (discussed in detail below) orradial potting followed by machining for larger devices as commonlyknown in the art.

Referring to FIG. 1, cylindrical housing 16 may be filled with stack ofmembrane mats 34. The membrane mats of stack 34 may be dimensioned toalmost fill the cavity of cylindrical housing 16 and may be stacked sothat they are substantially perpendicular to the longitudinal axis ofcylindrical housing 16. Cylindrical housing 16 and end cap 28 may bemade of any material. Such materials include polyolefins, polyvinylchloride, ABS, Noryl®, PVDF, PFA, or other fluorinated plastics,fiber-reinforced plastics, polysulfones, polycarbonates, polyamides,metals, etc.

The membrane mats of stack 34 may be bonded, welded, woven, nonwoven,knitted, or otherwise joined together in generally planar structurescontaining a plurality of joined together hollow fiber members 36, alsoknown as a disc module construction. The hollow fiber members 36 of themembrane mats may be of like materials and properties, or may be ofvarious materials and/or properties. These membrane mats of stack 34 maybe cut from a larger fabric to the desired size and shape to fit withincylindrical housing 16. Cutting may be accomplished by die cutting,ultrasonic cutting, knife cutting (e.g., hot), etc.

Hollow fiber members 36 may be fibers having a lumen and a wallsurrounding the lumen. The wall may have an exterior surface or shell.Hollow fiber members 36 may have solid walls, porous walls, ormicroporous walls (e.g., symmetric pores, asymmetric pores, skinnedmembranes and the like). These hollow fibers may be made of anymaterial. Such materials include polyolefins (e.g., polyethylene,polypropylene, polybutene, poly methyl pentene), polysulfones (e.g.,polysulfone, polyethersulfone, polyarylsulfone), cellulose and itsderivations, PVDF, poly phenyl oxide (PPO), PFAA, PTFE, otherfluorinated polymers, polyamides, polyether imides (PEI), polyimides,ion-exchange membranes (e.g., Nafion®), etc.

End cap 28 may be placed over open end 18 of cylindrical housing 16after stack of membrane mats 34 may be inserted into cylindrical housing16. End cap 28 may be united to cylindrical housing 16. This uniting maybe accomplished by any means, for example, gluing, welding, orthreading. End cap 28 may be joined along its contact surface withcylindrical housing 16. The cylindrical housing 16 and end cap 28 maysandwich the stack of membrane mats 34 and hold stack 34 in place duringthe next operation of the manufacture process.

Before spinning, all side ports 26 may be plugged. Because centrifugalforces may force the fluids to the exterior of cylindrical housing 16,where side ports 26 are located, plugging of side ports 26 may be doneto maintain the fluids in cylindrical housing 16 when the housing isspun in the following steps. Plugging of side ports 26 may be done byany device, including but not limited to, a cork, a plug, a stopper, acap, etc. Alternatively, the side ports may be added to housing 16following addition of the potting material, by, for example, drillingand tapping threaded openings.

The cylindrical housing 16 and end cap 28 may be mounted via outlet port32 or inlet port 24 onto a device that can spin the wafer-shaped module14 about the center longitudinal axis of cylindrical housing 16.

During spinning, a boundary fluid is introduced into either outlet port32 or inlet port 24. The boundary fluid, by action of centrifugal force,runs to the interior wall of cylindrical housing 16 thereby forming aboundary wall or partial boundary walls (depending on the internal shapeof cylindrical housing 16). The boundary wall may provide a space forthe peripheral edge 68 of stack of membrane mats 34 (external chambers42 and headspace 70), thus, keeping the ends of hollow fiber members 36open through the potting steps of the manufacturing process.

Potting material 38 may be introduced into either outlet port 32 orinlet port 24 after the boundary fluid is inserted. The potting material38, by action of centrifugal forces, runs to the boundary fluid on theinterior walls of cylindrical housing 16. Because the boundary fluid maybe inert to potting material 38 and may be denser than potting material38, potting material 38 thereby forms an annular ring or partial annularring (depending on the internal shape of housing 16) against theboundary fluid wall. Spinning is preferably stopped when pottingmaterial 38 has had sufficient time to solidify to a point that it willno longer run or substantially run (i.e., retains or substantiallyretains the shape of the annular wall).

Potting material 38 may be any material, for example, thermosetting orthermoplastic materials. These materials are chosen with the followingexemplary considerations: bond strength to the hollow fiber members 36,cylindrical housing 16 and end cap 28, mechanical strength, and chemicalresistance. Exemplary materials for potting material 38 include, but arenot limited to, epoxy and polyolefins.

The foregoing spinning step may be further illustrated as follows, itbeing understood that the invention is not so limited: Cylindricalhousing 16 may be spun horizontally. Spinning speeds may be about150-5000 rpm (depending upon, for example, potting viscosity). If cureis performed at ambient temperatures, spinning till substantially noflow could take up to as much as 24 hours or more; but, if cure is athigher temperatures, then cure times may be shortened, for example at50° C., spinning time may be dropped to about 2 hours, and at 65° C.,spinning time may be dropped to about 0.5-0.75 hours.

After potting material 38 may be cured, side ports 26 may be opened.This step allows the boundary fluid to be emptied or removed. Emptyingof the boundary fluid may be facilitated by spinning cylindrical housing16 as in the previous step after side ports 26 are opened. Once theboundary fluid is emptied, wafer-shaped hollow fiber module 14 may be inits final form.

This liquid-on-liquid process (potting material-on-boundary fluid)described above may eliminate the need to machine the embedded stacksafter potting and may eliminate any additional assembly steps. Thus,this process may significantly reduce the time and costs ofmanufacturing compared to the radial potting followed by machiningmethod known in the art. However, the instant invention could also bemade by the radial potting followed by machining method.

As shown in FIG. 5, and in accordance with one embodiment, a method 112of making wafer-shaped hollow fiber module 14 may be included in theinstant invention. Method 112 may include any steps for makingwafer-shaped hollow fiber module 14. In one embodiment, method 112 mayinclude the steps of: a step 114 of inserting stack of membrane mats 34into cylindrical housing 16 through open end 18; a step 116 of unitingopen end 18 with end cap 28; a step 118 of plugging side ports 26; astep 120 of spinning module 14 at a velocity about an axis through thelongitudinal center of cylindrical housing 16; an optional step 121 ofheating module 14 to a temperature while spinning making pottingmaterial 38 less viscous and facilitating the curing of potting material38; a step 122 of inserting a boundary fluid into inlet port 24 oroutlet port 32, where the spinning forcing said boundary fluid to forman annular boundary or partial annular boundaries around the walls ofcylindrical housing 16 and keeping the ends of hollow fiber members 36open; a step 124 of inserting potting material 38 into inlet port 24 oroutlet port 32, where the spinning forcing potting material 38 to forman annular ring or partial annular rings against the annular boundary; astep 126 of continuing to spin module 14 until potting material 38 iscured whereby bonding membrane mats of stack 34 to each other andsimultaneously bonding one end of stack 34 to closed end 20 and bondingthe other end of stack 34 to end cap 28, thereby defining an internalchamber 40 and at least one external chamber 42 within cylindricalhousing 16; and a step 128 of opening side ports 26 and emptying orremoving the boundary fluid.

In one embodiment of method 112, cylindrical housing 16 may have acylindrical internal shape forcing potting material 38 to define onecontinuous external chamber 42 around internal chamber 40. In anotherembodiment of method 112, cylindrical housing 16 may have a Double ‘D’internal shape forcing potting material 38 to define two externalchambers 42 around internal chamber 40.

The instant invention may be embodied in other forms without departingfrom the spirit and the essential attributes thereof, and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicated in the scope of the invention. Forexample, module 14 may include a cylindrical housing and two end capswith one end cap defining the inlet 24 and the other defining the outlet32.

1. A method of making a wafer-shaped hollow fiber module comprising thesteps of: inserting a stack of membrane mats comprising hollow fibersinto a cylindrical housing through an open end of said cylindricalhousing; uniting said open end with an end cap including a secondsealing surface and an outlet port; said housing having a closed endincluding a first sealing surface and an inlet port, and at least oneside port between said closed end and said open end; plugging said sideports; spinning said wafer-shaped hollow fiber module at a velocityabout an axis through the longitudinal center of said cylindricalhousing; inserting a boundary fluid into said inlet port or said outletport, where said spinning forcing said boundary fluid to form an annularboundary or partial annular boundaries around the walls of saidcylindrical housing and keeping the ends of said hollow fiber membersopen; inserting a potting material into said inlet port or said outletport where said spinning forcing said potting material to form anannular ring or partial annular rings against said annular boundary orpartial annular boundaries, said boundary fluid being inert to saidpotting material and being denser than said potting material; continuingto spin said wafer-shaped module until said potting material is curedwhereby bonding said membrane mats to each other and simultaneouslybonding one end of said stack to said closed end and bonding the otherend of said stack to said end cap, thereby defining an internal chamberand at least one external chamber within said housing; and opening saidside ports and emptying said boundary fluid.
 2. The method of making awafer-shaped hollow fiber module of claim 1 further comprising the stepof heating said wafer-shaped hollow fiber module to a temperature whilespinning making the potting less viscous and facilitating the curing ofsaid potting material.
 3. The method of making a wafer-shaped hollowfiber module of claim 1 wherein said spinning forcing said pottingmaterial to form an annular ring against said annular boundary.
 4. Themethod of making a wafer-shaped hollow fiber module of claim 1 whereinsaid spinning forcing said potting material to form partial annularrings against said partial annular boundaries.
 5. A wafer-shaped hollowfiber module made by the method of claim
 1. 6. A wafer-shaped hollowfiber module made by the method of claim
 2. 7. A wafer-shaped hollowfiber module made by the method of claim 3 and having circular mats. 8.A wafer-shaped hollow fiber module made by the method of claim 4 andhaving double D shaped mats.